Anunoby threw the ball to former Met, Jose Reyes. The two also exchanged jerseys before the game,
New York dropped two of three games in its first series under interim manager Andy Green, who took over when Carlos Mendoza was fired Friday.
The last-place Mets, who have lost eight of nine, went 2 for 16 with runners in scoring position and stranded 14 overall. They left the bases loaded in the fifth and eighth.
Senga, demoted to the bullpen this week after compiling a 10.08 ERA in seven starts, gave up four hits and struck out four in five innings. Mets opener Cionel Pérez pitched a perfect first in his first big league start after 283 relief appearances.
Philadelphia improved to 18-6 in one-run games, while the Mets fell to 7-15.